Westinghouse Electric Corporation

Westinghouse Electric Company LLC

James A Rex

David E Boyle

Bruce W Bevilacqua

David R Forsyth

David A Altman

Norman R Singleton

Richard E Schwirian

James R Chrise

Ching Yu

In a pressurized water reactor with all of the in-core instrumentation gaining access to the core through the reactor head, each fuel assembly in which the instrumentation is introduced is aligned with an upper internals instrumentation guide-way. In the elevations above the upper internals upper support assembly, the instrumentation is protected and aligned by upper mounted instrumentation columns that are part of the instrumentation guide-way and extend from the upper support assembly towards the reactor head in hue with a corresponding head penetration. The upper mounted instrumentation columns are supported laterally at one end by an upper guide tube and at the other end by the upper support plate.

Upper internals arrangement for a pressurized water reactor

A control rod guide tube mounting pin for engaging a hole in an upper core plate of a nuclear reactor pressure vessel has a resilient tubular portion with one or more axial crimps which flex allowing for resiliently fitting into a hole in an upper core plate without needing to enlarge or other machine the existing holes or drilling additional holes. Stainless steel mounting pins may be backfit into existing two pin mounting systems of control rod guide tubes adjacent to the outlet nozzles of the pressure vessels by removing the pins mounting the guide tubes adjacent the outlet nozzles to the upper core support plate; and then replacing the removed pins with stainless steel replacement pins.

Control rod guide tube mounting pin

A new system is provided for control rod guidance support with wear mitigating features in a nuclear reactor pressure vessel. The upper guide tube and the lower guide tube structures house the control rod when it is withdrawn from the fuel core. The upper guide tube has a top enclosure plate with a drive rod opening therethrough sized to provide a predetermined clearance space between the drive rod and the top enclosure plate and to direct coolant flow between the upper and outlet plenums and through the guide tube assembly to allow transmittal of upper plenum bypass cooling flow to the outlet plenum. Structure is provided for restricting coolant flow through the top plate clearance space to reduce control rod wear. A coupler secures the drive and control rods in end-to-end relation within the guide tube assembly. The coupler is located just below the top guide tube enclosure plate with the control rod fully withdrawn. The coolant restricting structure includes a flow restricting sleeve secured to the coupler and extending upwardly over the drive rod through the top guide tube enclosure plate. A flow restrictor is located above and secured to the top guide tube enclosure plate, and it has an upper portion disposed about and spaced from the flow restricting sleeve to provide a flow gap having a flow area substantially equal to the clearance space. The flow restrictor is otherwise structured to provide at least one contraction-expansion loss above the top guide tube plate for guide tube coolant flow through the flow gap.

System providing improved guidance support with restricted coolant flow

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Trafford, PA, United States of America

James A Rex